1. Field of the Invention
The present invention relates to a shading compensation circuit for correcting the shading properties of image data taken from an image capture device such as CCD and CMOS sensors and a control method thereof.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 2004-320645 discloses a shading compensation circuit 100 (see FIG. 17) that has an address generating means 102, address converting means 103, storage means 104 and arithmetic operation means 105. The address generating means 102 generates the addresses of image data with respect to either the main scanning direction or sub scanning direction, the image data being input from the image capture device for the image area. The address converting means 103 converts the addresses generated by the address generating means 102 in a specified conversion mode selected according to an input mode selection signal MA. The storage means 104 stores correction coefficients corresponding to the addresses converted by the address converting means 103. In the arithmetic operation means 105, arithmetic operation for shading compensation is performed, using a correction coefficient read out from the storage means 104 based on an address from the address converting means 103 and the image data input from the image capture device. In this case, since there is no need to store a correction coefficient for every image data piece in the image area, the storage area used for shading compensation can be cut down. In addition, a correction coefficient appropriate and corresponding to the shading properties associated with the main or sub scanning direction can be made to reflect in each image data piece.